It is already known that handwriting can be digitised by determining how a pen that is used to produce the handwriting is being moved. One way of carrying this out is to use a base for the handwriting that is provided with a position-coding pattern that codes coordinates for points on the base and also to provide the pen with a sensor that records the position-coding pattern locally at the pen point while the pen is being moved across the base. A processing unit, that can be placed in the pen or remotely from this, can thereafter decode the recorded position-coding pattern, so that the movement of the pen across the base can be determined as a series of coordinates.
In WO 01/26032, which has been assigned to the same Applicant as the Applicant for the present application, a position-coding pattern is described that can be used for digitising handwriting. The pattern is constructed of marks, which for example can be in the form of dots. Each dot has a nominal position, which can consist of an intersection between two lines in a virtual raster, for example a square grid. Each dot codes a particular value dependent upon its placing in relation to the nominal position. The dots can, for example, have four possible placings, one on each of the four raster lines that emanate from the intersection, with the four different placings coding four different values. The coordinates for a point are coded using a plurality of dots, for example 6*6 dots. Each dot contributes, however, to the coding of the coordinates for several points. If a sensor first reads 6*6 dots and thereafter is moved to the side or vertically by the distance of one dot, the sensor will read dots that code the coordinates for a new point. Each set of 6*6 dots thus defines a position in the total position-coding pattern. In this application, this type of pattern is called “floating”.
Using the position-coding pattern in the above-mentioned WO 01/26032, coordinates can be coded for a very large number of points, theoretically 436 points if each point is coded by 6*6 dots. All these points can be said to form an imaginary surface or constitute points in a coordinate system.
WO 01/71653, which has been assigned to the same Applicant as the Applicant for the present application, describes how the position-coding pattern described in WO 01/26032 can be used instead for general information coding.
WO 01/48685, which has also been assigned to the same Applicant as the Applicant for the present application, describes how the position-coding pattern in WO 01/26032 can be used to control the processing of the digital information that is recorded by means of the position-coding pattern. More specifically, the processing unit that decodes the position-coding pattern can store different digital templates, that define how information that is recorded from different parts of the position-coding pattern is to be interpreted. An e-mail template can, for example, specify that information, that is pairs of coordinates, recorded from a first field in the position-coding pattern on a base constitutes message information, that information recorded from a second field constitutes an e-mail address and is to be interpreted by ICR (ICR=Intelligent Character Recognition), and that information recorded from a third field is to be regarded as an instruction to send the message information originating from the first field to the e-mail address determined from the second field. The digital template thus comprises a description of which coordinate areas correspond to which fields. The processing unit utilizes this description in order to determine how decoded pairs of coordinates are to be processed.
In addition, WO 01/48685 describes how the position-coding pattern can be divided into pages and how the same digital template that is in the processing unit can be used for several pages in the position-coding pattern.
In order to make possible flexible information processing, different parties may want to have bases with different functions associated with different fields, with different numbers of fields, with differently placed fields and with differently sized fields. For this purpose, the processing unit may need to store a large number of different digital templates, which in addition may need to be updated and supplemented, as different parties want to create new bases.
This can constitute a problem, particularly if the processing unit has limited memory capacity and/or if it is time-consuming to amend, supplement and/or update the digital templates once these have been stored in the processing unit. This can, for example, be the case if the processing unit is in a portable user unit, such as the pen in WO 01/48685.
In the Swedish patent application SE 0103029-5, which was filed on 13 Sep. 2001 by the same Applicant as the Applicant for the present application and which was thus not available to the public at the time of filing SE 023853-7, from which the present application claims priority, a solution is proposed to the problem of the need to store a multitude of digital templates. More specifically, use is proposed of a coding pattern that comprises a plurality of marks, the position information being coded by a variation in a first parameter of the marks and additional information being coded by a variation in a second parameter of the marks. The additional information can be used for indicating or marking out fields of the type described above in the coding pattern on the physical base. Instead of the information about the different fields being in digital templates, it can thus be coded directly in the coding pattern, with the result that in principle any layouts for information processing can be achieved on physical bases and that the processing unit needs to store considerably less information than in the case with digital templates.
The additional information can alternatively be used to indicate in the coding pattern on the physical base whether a particular field in a digital template with several alternative fields is activated or not. By digital templates being combined so that in each digital template there is a description of a large number of alternatively useable fields and by the fields used in each individual case being activated by means of the coding of additional information in the coding pattern on the physical base, the number of digital templates required can be reduced.
The indication or activation of fields is achieved by the coding pattern in the different fields being divided into cells, each of which comprises a plurality of marks, and by each of the cells being allocated a predetermined value by means of the variation in the second parameter.
In the Swedish patent application SE 0201846-3, which was filed on 18 Jun. 2002 by the same Applicant as the Applicant for the present application and which was thus not available to the public at the time of filing SE 0203853-7, from which the present application claims priority, an alternative solution is described to the problem of the need to store a multitude of digital templates. More specifically, it is proposed in this application that the fields are indicated by means of a second position-coding pattern, which can be coded using a second parameter of the dots that are comprised in the first position-coding pattern. The second position-coding pattern codes coordinates in a second coordinate system which is different from the first coordinate system in which the first position-coding pattern codes coordinates. The second coordinate system is divided into partial areas with different associated functions. Thus in this case the processing unit only needs to store a description of the division of the second coordinate system into partial areas in order to be able to control the processing of the information that is recorded by means of the first position-coding pattern.
Another problem with the coding pattern described above and other similar coding patterns is that a base that is provided with this pattern can be copied while retaining its functionality. This property is undesirable for the party that is selling bases with the coding pattern. There is therefore a need to provide the base with coding patterns that are copy protected.